Stereoscopic plotting instrument



C. O. COOK STEREOSCOPIC PLOTTING INSTRUMENT l0 Sheets-Sheet 1 Filed March 28,

ATTORNEYS Nov. 28 1944. r c o. COOK STEREOSCOPIC' PLOTTING INSTRUMENT l0 Sheets-Sheet 3 Filed March 28, 1942 INVENTOR C.O.COOK- 3m AT TORNEYS c. o. cook STEREOSCOPIC PLOTTING INSTRUMENT Nov. 28 1944.

Filed March 28 1942 10 Sheets- Sheet 4 1NVENTOR C.O.COOK

v Nov. 28, 1944. c. o..co oK' STEREOSCQPIC PLOTTING INSTRUMENT 1O Sheets-Sheet 5 Filed March 28 1942 v v m3 S1 NS 40..

INVENTOR C.O.COOK V ATTORNEYS Nov. 28, 1944. c. o. COOK STEREOSCQPIC PLQ'ITING INSTRUMENT 10 Sheets-Sheet a Fi led March 28, 1942 INVENTQP.

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a BY "m a; ATTORNEYS INVENTOR C.OY.COOK

l0 Sheets-Sheet 7 g ATTORNEY S C. O. COOK STERB OSCOPIC PLOTTING INSTRUMENT Filed March 28, 1942 Nov. 28, 1944.

Nov. 28, 1944.

c. o. cooK STEREOSCO PI C PLOTTING INSTRUMENT l0 Sheets-Sheet 8 Filed March 28, 1942 INVENTOR C.O.COOK

ATTORNEYS Nov. 28, 1944. c. o. COOK STEREOSCOPIC PLOTTING INSTRUMENT Filed March28, 1942 i0 Sheets-Sheet 9 vvm mm. 11mm.

:INVENTOR NOV. 28, 1944. Q Q 300 STEREQSCOPIC PLO'I'TING-INSI'RUMENT Filed March 28, 1942 Y 10 Sheets-Sheet 10 S Y E N R T A Patented Nov- 28, 1944 i UNITED STATES PATENT OFFICE srnauosoorrc rLo'rrmG ms'rnummr Charles (l. Cook, Ta koina Park, Md. Application March 2}, 1942, Serial No.436,697

.(Granted under the aet of March 3. 1883, as amended April 30, 1928; 370 0. G. 757) 7 Claims.

This aprilication is made under the act of March 3, 1883, as amended by the" act of April 30, 1928, and the invention herein described. if patented, may be manufactured and used by 'or for the Government of the United States of America for governmental purposes without the payment to me of any royalty thereon.

This invention relates to the art of delineating I and compiling maps from aerial photographs having stereoscopic overlaps. I

In general, this invention comprises an instrument by mean of which a pair of aerial photographs having a stereoscopic overlap can be viewed stereoscopically simultaneously with a mapping surface upon which themap is to be: produced, so that an index mark "which can also be viewed simultaneously and which is attached to a tracing device in contact with the mapping surface can be moved to follow along lines of the model which are delineated on the mapping surface by the tracing device.

The following descriptionconsidered together with the accompanyin drawings, will disclose this invention. more fully, its objects and advantages, so that a complete understanding may be had. by those skilled in the art.

In the drawings:

Figure 1 is a front elevational view of one of the preferred embodiments of this invention.

Figure 2 is a side elevational view of the embodiment illustrated in Figure 1.

Figure 3 is a plan view of the same embodiment.

Figure 4 is a fragmentary section along the line 4--4 of Figure 3.

Figure 5 is an isometric view of the piece frame.

Figure 6 is a section along the line 6-6 of Figure 5. I

jFigure '7 is a partial plan section along the left eyeline 1--'I of Figure 1.

Figure 8 isa section along the line 8-8 of Figure 7.

' Figure 9 is an enlarged section along the line 9 9 ofFiguIe .3. I

Figure 10 is a section along the line lfl-l'll of Figure 3.

Figure 11 is an isometric view of the mounting for the left semi-transparent mirror.

Figure 12 is a vertical section of the tracing stand along the line |2-|2 of Figure 1.

Figure 13 is a vertical section of a frame carrying a modified arrangement of mirrors in the optical system.

Figure 14 is a plan view of the tracing stand.

Figure 15 is awlring diagram for the incandescent lamps.

Figure 16 is a. modified form of the invention for use with high oblique photographs.

Figure 17 is a iront elevational view of another modlfication of this invention.

Figure 18 is a section along the line of Figure 17. r v

Figure 19 is an enlarged front elevational view of one of the phototables and supports.

Referrin with more particularity to the drawings, in which like numerals designate like parts,

'- the embodiment illustrated in Figures 1 to 12 comprises a; suitable frame 30 whichis normally supported onamapping surface 3| by means These adover th mapping surfacepfor which purpose bubble levels 33 and-34am fixed to the frame.

on top of the instrument there is mountedi theoptical system, which includes a stereoscope for viewing photographs having a stereoscopic overlap. This optical system in contained in housings 35 and 36 and comprises eye-pieces 31.

and 38 and eye-piece mirrors and 40, respectively, facing outwardly and upwardly at an angle of about 45?. These eye-pieces and their corresponding eye-piece mirrors are mounted in longitudinally movable frames 4| and 42. Each of these frames carries a housing 43 consisting of a top portion .44 and end walls 45 and 46 which carry horizontal flanges. 41 and 48, the ends of which are slidable in longitudinal grooves l9 and 50' of supporting members 5| and 52 secured to the frame of the instrument. Within the housing 43 theeye-piece mirror is disposed. Guides 53 and 54 extend from the flanges 4'! and 48 in thegrooves 49 and 5.0 to stabilize the movement of the frame. The top portion 44 isintegral with the barrel 51 of the eye-piece which contains a lens 58. The barrels of 'both the eye-pieces are disposed through longitudinal slots and iii of the housings 35 and 36, respectively, to permit adjusting movements which are necessary in order to accommodate! the eye;

span of different individuals. The eye-piece mirrors 3.9 and '40. are disposed below their respective eye-piece lenses. Each of these mirrors is adjustably mounted between three springs 152 on one side andxthree abutment screws on the other side. Withinthe housings 35 and 36 there are secured wing mirrors 68 and 59, respectively, parallel to and facing the mirrors 3,9 and 40. respectively. However, parallelism between these correspondingmirrors is accomplished by adjusting the mirrors 39 and 40 with the abutment screws 85.

The frames 4| and 42 are provided with longitudinal racks 10 and 1| which engage pinions 12 and 13 fixed to shafts 14 and 15. These shafts are rotatably mounted through the housings 35 and 38 and on the exterior are provided with knobs 18 and 11 to permit rotating the shafts and pinions manually, so as to mOVe the frames 4| and 42 independently in the grooves 49 and 50. Each of the frames 4| and 42 is provided with a reference mark 18 which moves adjacent a scale 19 on the supporting member 5 I.

Between the mirrors 39 and 40 and 88 and 89, other mirrors 80 and 8I are disposed on movable frames 82 and 83. These other mirrors, however,

are half-silvered or semi-transparent with the reflecting surface of each facing and being parallel to its corresponding eye-piece mirror. The mirrors 80 and 8| are mounted on their frames between three springs 84 and three abutment screws 81 to permit the making of adjustments. These frames are supported on bases 90 and 9| slidably disposed in grooves 92 and 93, which grooves are below and parallel to the grooves 49 and 50, in the members 5| and 52. Longitudinal racks 94 and 95 are secured to the underside of the bases 90 and 9|, which racks engage pinions 98 and 91 secured to shafts 98 and 99, said shafts being rotatably mounted through the housings 35 and 38. The other ends of the shafts 98 and 99 .are provided with knobs I and IOI to facilitate rotation manually. Each of the bases 90 and 9| is provided with a reference mark I02 adjacent a scale I03 on the supporting member Should it be desired to shift the field of view of the mirrors 80 and 8| closer to the center of the instrument, this part of the instrument may be modified as shownin Figure 13 by securing sets of parallel mirrors I 04and I05 perpendicular to the mirror 80, and a similar set of mirrors parallel to the mirror 8|, on frames such as the frame 82 beneath the mirrors 80 and 8|, substantially as illustrated. The housings 35 and 38 are provided with hinged tops I08 and I09 having apertures H0 and III over which there are mounted tubular housings H2 and H3 for incandescent lamps I I4 and H5, the function of which will be hereinafter explained.

Beneath the housings 35 and 38 phototables I 8 and H1 are disposed, each comprising a platen II8 pivoted on trunnions H9 and I20 between the parallel arms I2I and I22 of a horizontal U-frame I23. The frame I23 is supported by means of a sleeve'bracket I24 slidably engaging the cross arm I25 of non-circular cross-section of the frame I23. The bracket 124 is integral with a horizontal stub shaft I28 at right angles to the cross arm I 25 which is rotatably set in a bearing I21 on the end of a bar I28. The shaft I28 is held in the bearing I21 by means of a .pin I29 engaging a concentric groove I30 of the said shaft. The bar I28 is of a non-circular cross-section and is longitudinally slidable through another sleeve bracket I3I mounted for vertical movement on an upright I32 comprising one of the structural members of the frame of the instrument. The various movements permitted by this arrangement may be controlled by any suitable means. The means illustrated comprise a vertical rack I33 on the upright I32 and a horizontal rack I35 on the bar I28 engaging conical worms I38 and I31,-respectively,.which are rotatably mounted on the bracket I3I by means of shafts I38 and I39. Knobs I40 and MI are secured to the shafts I38 and I39 for imparting rotation manually. This provides for control-of vertical motion and longitudinal hori- "zontal motion. Lateral horizontal motion is conthumb screw I50 on the shoulder I48 abuts the ear I48 against the force of the spring I49. Consequently, by turning the thumb screw I50 the whole phototable pivots about the bar I28, either against or under the action of the spring I49, as the case may be. Pivotal movement of the platen II8 on the trunnions H9 and I20 is similarly accomplished by means of a thumb screw I5I on an ear I 5IA extending from the U-frame I 23 beneath the platen. Said screw abuts the under side of the platen against the force of a compressed spring I52 between the top of the platen and an ear I52A extending from theframe above the platen. A short upright pin I53 is secured to the center of each platen II8 to engage pivotally the centers of photographic prints. The prints are pivotally moved about these pins by means of a thumb screw I54 rotatably disposed ,in a nonradial direction on a bracket I55 fixed to the I platen. The'inner end of the thumb screw I 54 is provided with a friction pad I58 of any suitable material, such as sponge rubber, to engage the s'urface of photographs placed on the platen. By these means photographs placed on th platens can be tilted, tipped, swung, and moved in three coordinate directions.

Photographs placed on the platens II8 are illuminated by fluorescent lamps I51 and I50 or by the incandescent lamps H4 and H5, or both. In order to compensate for a difference in density or tone between pairs of photographs, the intensity of light from the incandescent lamps is made independently adjustable by means of rheostats I59 and I80, as illustrated in the wiring diagram (see Figure 15).

Complementary to the parts described above is a tracing stand I8I, similar to that employed with the conventional multiplex aero-projector (see Engineering Applications of Aerial and Terrestrial Photogrammetry (1938) by B. B. Talley, page 228), which comprises a U-shaped base I82 adapted to be moved independently over the mapping surface 3|, upon which the instrument is supported. Uprights I83 and I 84 are secured to the base I82, upon which a horizontal opaque ledge or disc I85 is supported for vertical movement by means of sleeves I88 and I81 connected by a bar I88 slidable on said uprights and attached to said disc by an arm I89. The uprights I83 and I84 are connected at the topby a brace I10, and the ledge I85 is moved on said uprights by means of a vertical micrometer screw |1I pivotally supported between said brace and the base I82. The screw I 1| is threadedly engaged with a boss I12 fixed to the bar I88, and rotation of the screw is accomplished manually by means of a thumb grip I13. The ledge IE5 is provided on top with a reference mark I14 which is commonly referred to as the floating mark. It is well known that this mark may the floating mark I14 is brought.

compensate for this diiference.

be either a mechanical configuration such as a -V,X, or a point source of light shining through a pinhole in the center of the ledger Directly beneath this mark there is secured to the base III a pencil I15, or other tracing implement. by means of a rigid arm I" and a holder I11.

1 ,The point of the'pencil is adapted to rest on the mapping surface. II, and its position is adjusted thereto by means of set screws I18 on the said holder. One of theuprights is provided with a vertical scale I19 for indicating relative positions of the ledge.

The instrument is operated as follows:

A pair of vertical photographs or prints having a stereoscopic overlap is mounted on the. platens II8with the center of each print over the center of each platen beneath the friction When one contour line has been mapped, the

pads I58. The prints are held in this. position by forcing the pins I53 through their centers.

The prints are viewed through the eye-pieces 31 and 38 and swung into stereoscopic correspond:

. once by turning the thumb screws I54 and adlusting the position of the prints with respect to the field of view of the stereoscope by means of the other adjustments provided. The observer,

in looking through the eye-pieces, will then see a. spatial model of the image represented by the stereoscopic overlap reflected. from the mirrors 08 and 69 through the semi-transparentmirrors eye-pieces by the mirrors 39 and 40. The observer also sees, at thesame time, the image of objects in the field of view of the silvered portions of the mirrors80. and 8I reflected to the mirrors 39 and 40. In this latter, fleld of view The spatial height setting 01 the floating mark is changed by turning the thumb grip I13 to bring the floating mark to the next contour elevation desired, and the procedure is repeated. This is done for each contour elevation until the map is completed. q

In order to use this invention for making maps from high oblique photographs, that is, photographs which have been taken at a substantial angle to the vertical, such as around the instrimient should besupported over the mapping surface'sb that the lines of sight of the stereoscope are in a plane at an angle approximating the angleof obliqueness. This may be accomplished by changing the structural frame, as illustrated or stereoscopic model can be .horizontaiizedin tilting and tipping of the camera about axes which are not in the plane of the photograph,

the tipping and tilting movements of the platens in the end view of Figure 16, all other parts of the device being the same relative thereto. This arrangement places the tables for supporting the photographs normal to the approximate angle of obliqueness relative to which they can be moved in three coordinate directions.

A further modification of this inventionill-us- 80 and 8I and thenreflected up through thewgo trated in Figures 17, 18, and. 19 permits the mounting of a series of consecutive overlapping photographs and meansare provided for viewing anyoonsecutive pair by shifting the optical system bodily thereover. This modification comprises asuitable frame structure I80 on the top of which there is secured longitudinal parallel bars I8I W and I82, upon which there is slidably mounted a carriage I83 which supports a. housing I 84, for the optical system. This system comprises a pair of horizontal eye-pieces I85 and I86 through the front of the housing, a half-silvered or semi-transparent mirror I81 extending in front of. both eye-pieces at an angle of approximately 45?, and another mirror I89 of the full reflecting type in front of and parallel to said half-silvered or semi-transparent mirror. Between the mirror must be complemented by shifting their positions in one ormore coordinate directions to In using the instrument for making. plani- 'metric maps, the floating mark I14 is moved to a position where it appears to, the operatorzlooking through the eye-pieces 31 and 38 to contact the surface of the spatial model at a; point on the extreme end of a planimetric line, such as a drainage line, and the point of the pencil I15 is placed in contact with the mapping surface 3|, upon which the instrument is supported. The tracing stand IGI isthen moved so that the floating mark I14 follows. the selected planimetric line of the model, the while continually 'changing the elevation of the floating mark by turning the thumb grip I13 to cause the float ng mark to appear to contact the surface of the model at every point along the planimetric line traversed. When this traverse is completed, another planimetric line is selected for which the same procedureis followed. This is repeated for every desired .planimetric'line, of the model to complete the map.

To use the instrument for making contour maps, the floating mark I14 is set at a height so that it appears to contact the model at a point on a, selected contour elevation thereof, and the pencil I15 placed in contact with the I81 and each eye-piece I85 and. I88, there are disposed inverting prisms, such as the prism. Hi.

The carriage I83 is supported on racked tracks I93 and I94 on the bars I8I and I82 by means of V shafts I95 and I98 rotatably mounted. in bear ings I91and I98, and I99 and 200, respectively, on either side of the carriage. These shafts are provided with pinions 20l and 202 engaging the racked track I93 and pinions 203 and 204 engag ing the track I94. One of said shafts, say the shaft I98, extends forwardand is provided with a knob 205 to facilitate manual rotation thereof.

Below the carriage I83 there is mounted arm: of tables 208'adjustable inthree coordinate directions and also for tip and tilt as in the first embodiment illustrated. These tables are independently mounted on a longitudinal bar 201 by means of a removable sliding hanger 208, one for each table. Each hanger carries a shoulder 209 which rests on a. beveltrack 2I0 of the bar 201 and alip 2IIA'which engages the back of said bar 201. A vertical post 2II of non-circular l cross-section is attached for vertical movement to each hanger 208. To the bottom of each post 2| I i there is attached for movement in a direction perpendicular to both the bar 201 and post 2II an arm 2I2 of non-circular cross-section,

which arm operates in a sleeve 2 I2A fixed to the bottom of the post 2I I. To the end of the post 2 a collar 2l3 is rotatably mounted. Secured to said collar 213 is the cross-arm 2140f. a U- frame 2| 5. Between the parallel arms 2l6 and 2| 1 of said U-frame a platen 218 is pivotally mounted on trunnions 2|9 and 220.

Movement of the sliding hanger'208 on the bar 201 is accomplished by a pinion 22-! fixed to the end of a shaft 222 rotatable on the hanger, which pinion engages a rack 223 extending throughout the length of the bar; This engage=- ment serves as a third point of support for the hanger on the bar 201. A knob 224'for turning the shaft 222 is provided. Movement of the post 2 on the bracket 208 is controlled by a thumb screw 225 on the said post, threadedly engaging an ear 226 extending from the bracket 288. The arm 2l2 is movedv relative to' the post 2 by means of a pinion 221 fixed to a shaft 228 on the sleeve 2l2A which engages a rack 229 on the said armL Rotation of the U-frame M5 on the collar 2l3'about the end of the arm 2l2 is-accomplished by movement of projections 230 and BI from said frame relative to aprojection 231A from said arm, which movement is controlled by an abut ment screw 232 against the force of an opposing spring 233. Similarly, the platen 218 is pivotally moved on its trunni-oris by means of an abutment screw 234 on the frame 2l5 against the force of an opposing spring 235.

The center of each platen 218 isprovided with a short upright pm 236 for pivotally engaging a photograph, and, when so engaged, the photograph may be swung aboutthe pin by means of a thumb screw 231 disposed in a non-radial position on a bracket 238 attached to the platen.

pad 239, like the pad l 55 in the embodiment first described.

Photographs on the platens are illuminated by incandescent lamps 240 and I mounted in tubes 242 and 243 on the housing I84. The intensity of light from these lamps is independently controlled by rheostats (not shown), in a Wiring system similar to that shown in Figure 15. The entire instrument is supported by adjust-- able legs 2. which, in use, rest on the mapping surface. A tracing stand 245 like the one described in the first embodiment is also used in connection with this embodiment.

Having thus described my invention, I claim:

1. A' plotting instrument comprising a frame adapted to be supported on a horizontal mapping surface, tables supported by said frame for mounting stereoscopic pictures, means for tipping, tilting, and moving in three coordinate directions each of said tables with respect to said frame, a single reference mark below said tables movable over said mapping surface, and an optical system for viewing said pictures stereoscopically and for simultaneously viewing said reference mark..

3. Aplotting instrument comprising a frame' adapted to be supported on a horizontal mapping surface, a row of tables supportedibyz said frame for mounting. aseries of pictures: which are related through stereoscopic overlaps, means for tipping, tilting, and moving-lnthreecoordinate directions eachof' said'tables with respect to said frame,.rn'eans for pivotally turning said pictures on said: tables, a single reference mark below said tables movable oversaid mapping surface, a carriage movable over saidtables, means on said frame ,for supportingsaid carriage, an

optical system carried by said carriage .forvlewing consecutive pairs of i said; pictures and-for simultaneously viewingsaid reference mark. 1

4. A plotting instrument comprising aframe adapted to be supported on a horizontal-mapping surface, tables support'edby said frame .for mounting stereoscopic pictures, means for tipping, tilting, and moving, in threecoordinate directions each of said tables with respect to said frame, a single reference'mark belowsaid tables movable over said mapping surface, a

- stereoscope for viewing said pictures stereoscopmark.

ically, and means associated with said stereo-- scope for simultaneously viewing said reference 5. A plotting instrument comprising a frame adapted to be supported on a horizontal map- The inner end of the thumb screw 231 carries a 2. A plotting instrument comprising a frame adapted to be supported on. a horizontal mapping surface, tables supported by said frame for mounting stereoscopic pictures, means for tipping, tilting, and moving in three coordinate directions each of said tables with respect to said frame, means for pivotally turning said pictures on said tables, a single reference mark below said tables movable over said mapping surface, and an optical system for viewing said pictures stereoscopically and for simultaneously viewing said reference mark.

ping surface, tables supported by' said frame for mounting stereoscopic pictures, means for tipping, tilting, and moving in three coordinate directions each of said tables with respect to said frame, a single reference mark supported on andmovable over said mapping surface, astereoscope for viewing said pictures stereoscopically,

and semi-transparent mirrors associated with said stereoscope for simultaneously viewing said reference mark. r

6. A plotting instrument comprising a frame adapted to be supported on a horizontal mapping surface,-tables supported by saidframe for mounting stereoscopic pictures, means for tipping, tilting, and moving in three coordinate directions each of said tables with respect to a said frame, a single reference mark supported on and movable over said mapping surface,.a

stereoscope for viewing said pictures stereoscopically, said stereoscope including eye-pieces, means for adjusting the relativepositionsof said eye-pieces to accommodate the eye bases of dif-' ferent observers, and means associated with. the

stereoscope for simultaneously viewing said reference mark.

'1. An instrument for plotting maps from oblique photographs having a stereoscopic overlap comprising a frame adapted to be supported on a horizontal mapping surface, a stereoscope for viewing said pictures stereoscopically, said stereoscope being tilted at an angle to the plane of the mapping surface corresponding approximately to the angle of obliqueness'of the, photographs, tables for supporting said photographs in the field of view of said stereoscope, means for tipping and tiltingv said tables, means for moving said tables in three coordinate directions,- and means associated with saidstereoscope for simultaneously viewing a single floating mark over themapping surface when the mark is between said tables and said mapping surface.

CHARLES O. COOK. 

